In hot, dry climates such as the desert regions of the southwestern United States, evaporative cooling systems are widely used for cooling dwellings and other architectural structures. These cooling systems are popular because of their relatively low cost compared with refrigeration cooling or air conditioning systems. Evaporative coolers operate on the principle of the cooling effect provided when water evaporates from a saturated pad through which warm, dry air from outside the dwelling is passed into the dwelling under control of a fan or blower.
For most effective use of an evaporative cooler it is necessary to exhaust the air continuously from the building and to bring fresh air into the building through the evaporation pads of the cooler. In the U.S. Pat. No. to Cox, 4,047,475, assigned to the same assignee as this application, a ventilating damper assembly is disclosed for permitting the removal of air from the rooms of a dwelling through a damper assembly mounted in the ceiling of the room into which the cooled air is introduced by the evaporative cooler system. Typically, a ventilating damper of the type disclosed in the 4,047,475 patent is placed in the ceiling of each room to remove the air from the rooms and vent it into the attic of the building from which it passes outside through the conventional attic vents. Ventilating damper assemblies of the type disclosed in the 4,047,475 patent have met with widespread commercial success and result in improved efficiency of cooling operation with the evaporative cooler systems with which they are used.
Many homes, however, have preexisting refrigeration cooling or air conditioning systems in them, since when energy costs were low such systems generally were preferred over evaporative cooler systems. With the significantly increased energy costs which are prevalent throughout the United States today, however, the current trend in arid or semi-arid climates is back to evaporative cooling systems or a combination of evaporative cooling systems and refrigeration systems. In combination systems, the refrigeration cooling is only employed during the more humid months of the year, while the primary cooling of the dwelling is effected by the evaporative cooler. In preexisting installations, it has been common to install an evaporative cooler and connect the outlet duct from the cooler directly into an existing air conditioner duct. Appropriate dampers then are provided to switch the air flow between the refrigeration air conditioning unit or the evaporative cooler.
A problem is encountered in most such conversion installations, however, in that refrigeration air conditioning generally moves a much lower quantity of air per minute than an evaporative cooler; so that the air conditioning ducts in a home or other building originally built for refrigeration air conditioning are too small to adequately handle the double or triple amount of air movement required for evaporative cooler systems of the same or similar cooling capacity. For example, a five (5) ton refrigeration system cools air only at the rate of 2,000 cubic feet per minute, whereas an evaporative cooler of similar refrigeration capacity moves air at 4,500 cubic feet per minute up to 6,500 cubic feet per minute. If the duct work in the building is intended for the lower 2,000 cubic feet per minute air movement, the addition of a much higher capacity evaporative cooler blower for introducing air into such duct work overloads the carrying capacity of the duct work. This results in poor performance of the evaporative cooler system which is added into the refrigeration system.
In addition, the evaporative cooler typically is mounted on the roof of a building, and the interconnection to the existing duct work generally is a right-angle connection downwardly from the cooler into an opening cut into the top of a preexisting refrigeration duct. Consequently, the high volume air flow from the cooler impinges at right angles upon the opposite side of the preexisting duct. This results in a large amount of turbulance and back pressure; so that in some cases, very little air flow from the evaporative cooler actually takes place into and from the interconnection between the cooler outlet and the air conditioner duct input.
Consequently, it is desirable to provide improved operating results from conversion of refrigeration cooled systems to evaporatively cooled systems to overcome the shortcomings of previous systems. It further is desirable to overcome the disadvantages present in currently practiced conversion techniques at a minimum cost and in a simple and efficient manner.